Vitiligo is a long-term skin problem that produces white depigmented patches that develop and grow in certain sections of skin. In humans, melanin is the primary determinant of pigment or skin color. The melanin in the skin is produced by melanocytes, which are found in the basal layer of the epidermis. Various ethnic groups produce more melanin in the skin. Some humans have little to no melanin synthesis in the skin and this condition is known as albinism.
Aside from cases of contact with certain chemicals, the cause of vitiligo is unknown. Research suggests vitiligo may arise from autoimmune, genetic, oxidative stress, neural, or viral causes. Vitiligo is typically classified into two main categories: segmental and non-segmental vitiligo. Half of those affected show the disorder before age 20, though most develop it before age 40. The global incidence of vitiligo is less than 1%, with some populations averaging 2-3% and rarely as high as 16%.